This invention relates generally to mobile lifting apparatus and, more particularly, to a fork attachment for a lift vehicle of the "boom truck" type.
One particularly versatile kind of mobile lifting apparatus is the type having a pair of horizontal, extendable booms supported by vertical hydraulic cylinders that are carried on a self-propelled chassis. Such an apparatus, which is exemplified by the "boom truck" mobile lifting apparatus manufactured and distributed by Riggers Manufacturing Co., Inc., of Franksville, Wis., is described in U.S. Pat. No. 4,763,800. Such an apparatus provides a low profile machine that can lift a load vertically and transport it horizontally even where the overhead clearance is extremely limited. Because the horizontal booms are themselves extendable, loads can also be lifted and placed ahead of the apparatus in places where the apparatus itself cannot be driven. Loads can even be carried atop the booms, in effect using the apparatus as a gantry or jack. In many ways, the versatility of the machine is limited only by the imagination of the operators and riggers who call upon the machine to perform various tasks.
Although highly versatile, there are, nevertheless, certain tasks that the "boom truck" type of mobile lifting apparatus has, heretofore, been unable to perform easily and quickly. One such task is lifting and transporting loads that are carried on pallets. Although slings can be rigged to lift such Palletized loads with a conventional "boom truck," this requires additional labor and in large measure negates the benefits and convenience of palletizing the load in the first place.